Swedish energy technology company Rebaba is developing a way to reuse electric vehicle batteries after they leave cars. The company, led by co founders Paula Runsten and Felix Kruse, uses recovered EV batteries to build energy storage systems for homes, businesses and industrial sites. The idea is to extend the useful life of batteries that have already been produced.
Demand for battery storage is also growing. According to the International Energy Agency, 108 GW of new battery storage capacity was deployed worldwide in 2025, an increase of 40% from the previous year. The IEA describes battery storage as the fastest growing power technology today, as electricity systems add more renewable generation and require more flexibility.
Rebaba has raised $4.6 million, or SEK 44.1 million, in an oversubscribed seed round. Sistafund led the financing alongside EIT Urban Mobility, with participation from Rockstart, BlackWood, The Blue Minds Company, RadCap, Bo Kaunitz, Maximilian Wittmann, Fredrik Hagenius and Charles Rosier, as well as other investors.
Reusing batteries can extend the value of materials that were originally produced for electric vehicles. The IEA estimates that around 1.2 million EV batteries could reach the end of their lives in 2030, with that figure rising to 14 million by 2040. The agency says reuse and repurposing can contribute to making battery supply chains more circular.
Turning those batteries into stationary storage still comes with practical challenges. Companies have to deal with safety and warranty requirements, understand how much useful life remains in each battery and compete with falling prices for newly manufactured batteries. According to the IEA's Global EV Outlook 2026, together these factors can reduce the economic attractiveness of repurposing used EV batteries.
Rebaba combines recovered EV batteries with its own control technology. Its systems can store locally generated electricity, move electricity use to different times of day, reduce periods of peak demand and provide grid balancing services. These are practical uses for stored electricity.
"Europe’s energy transition depends on scaling storage fast, without creating new dependencies on scarce raw materials or costly imports. Rebaba turns retired EV batteries into high-performance storage systems that can be built locally and compete on price. That is what convinced us to lead this round: circularity without compromise, and a team with the potential to build a European leader in energy storage." — Marie Geneste, Partner at Sistafund
The new capital will support an increase in production and Rebaba's expansion across Europe. The company has been producing systems for one year at its CircularHub in Stockholm and currently has commercial deployments operating across Sweden.
One priority is expanding the Stockholm CircularHub to a production capacity of 40 MWh per year. Rebaba estimates that operating at this level could avoid approximately 4,000 tonnes of CO2 annually. The company also intends to hire people across several roles as production grows. The funding will support that expansion.
Rebaba is also moving into additional European markets. It has signed previously undisclosed commercial agreements in Sweden and Denmark and is taking steps toward establishing more manufacturing CircularHubs outside Sweden, with the aim of producing systems closer to the markets they serve.
The company's distribution network already covers several parts of Europe. Agreements are in place with KP Energy in Sweden, OKQ8 across wider Scandinavia, nanuq in Germany, Austria and Switzerland, and Smartports in France. Rebaba says further European distribution partnerships have also been signed but have not yet been announced.
Rebaba builds circular energy storage systems using batteries recovered from electric vehicles. According to the company, EV batteries are retired with 70% to 80% of their useful life remaining, which creates an opportunity to use them again in energy storage systems. The batteries therefore get another use after leaving vehicles.
The company currently sells two products. Companion is a compact 40 kWh cabinet based storage system intended for homes and smaller commercial installations. Containerised is designed for larger commercial and industrial applications where more storage capacity is required.
Rebaba says its platform can work with batteries from virtually any electric vehicle. Its own technology handles the complexity involved in integrating different batteries, while the rest of the system can be assembled using standard components available locally. This setup is intended to make local manufacturing and expansion into additional markets easier.
"The Rebaba platform is built to work with virtually any electric vehicle battery. By keeping the complexity within our core technology, we can assemble the rest of the Rebaba system from standard, locally available components. In practice, this means that essentially any technician, anywhere in the world, can build a Rebaba system." — Felix Kruse, Co Founder and CTO of Rebaba
Rebaba targets EV charging infrastructure, residential and commercial buildings, and industrial users. Customers can use its systems to reduce energy costs, deal with limits on grid capacity, improve operational resilience and generate revenue from energy services.
Sistafund led the seed financing. The pan European venture capital fund invests in early stage companies, with areas of interest that include sustainability and deep technology. It also backs female founders and gender balanced founding teams.
EIT Urban Mobility participated alongside Sistafund. Founded in 2019 as an initiative of the European Institute of Innovation and Technology, an EU body, the organisation supports companies working on sustainable mobility and gives startups access to funding, markets and industry networks.
The round also included Rockstart, BlackWood, The Blue Minds Company, RadCap, Bo Kaunitz, Maximilian Wittmann, Fredrik Hagenius and Charles Rosier. Including the latest seed round, Rebaba says it has secured $7 million, or SEK 67.1 million, in equity and non dilutive funding since its founding.
